I understand what both of you are saying. I'm 6'-3" with a 32" inseam, so that underseat space is important to me. But fortunately, my underseat personal item is not large; I a 7"x4"x10" shoulder bag with a couple of bottle carriers clipped on, which doesn't take much of my foot space, and once the plane is at altitude I pull the whole thing out and hang it on the tray table, which frees up my foot space. I have seen others with really large items protruding from their underseat space so far that they had to keep their feet tucked under their own seat the whole flight, and I couldn't imagine twisting myself up like that for multiple hours.

That's why seat choice is so important to me - I need a seat with a standard seat ahead of it, so I have that foot room and the tray table. And it's one reason why I like WN's boarding process - as long as I get on the plane early enough, I have a choice of seats, even if I need to go all the way to the back of the cabin. These days, I can't really fit in one seat any more due to weight gain, not to mention that my shoulder have always been too wide for a WN seat and infringe on the seat next to me, so I preboard as a COS and have an even wider selection. That too is a useful part of WN's boarding process, allowing me to easily find a pair of seats together somewhere in the portion of the cabin where the walls are at their maximum diameter and get settled comfortably before the rest of the pax come aboard.

I also feel like the boarding process is faster than I remember from the days before I flew WN all the time, though I have heard that studies show no appreciable difference in time between the boarding methods. Still, even if it's just an illusion, I like that it feels faster - anything that makes the flight go more quickly and gets me to my destination happier is a good thing.